Add cache for index fields

Author: xplicit

.vscode/launch.json

@@ -6,7 +6,7 @@
             "type": "coreclr",
             "request": "launch",
             "preLaunchTask": "build",
-            "program": "${workspaceRoot}/tests/ServiceStack.OrmLite.Tests/bin/Debug/netcoreapp1.0/ServiceStack.OrmLite.Tests.dll",
+            "program": "${workspaceRoot}/tests/ServiceStack.OrmLite.Tests/bin/Debug/netcoreapp1.1/ServiceStack.OrmLite.Tests.dll",
             "args": ["--test=ServiceStack.OrmLite.Tests._TypeDescriptorMetadataTests.Can_add_AutoIncrement_Id_at_runtime"],
             "cwd": "${workspaceRoot}",
             "stopAtEntry": false,

src/ServiceStack.OrmLite/IndexFieldsCacheKey.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Data;
+
+namespace ServiceStack.OrmLite
+{
+    public class IndexFieldsCacheKey
+    {
+        int hashCode;
+
+        public ModelDefinition ModelDefinition { get; private set; }
+
+        public IOrmLiteDialectProvider Dialect { get; private set; } 
+
+        public List<string> Fields { get; private set; }
+
+        public IndexFieldsCacheKey(IDataReader reader, ModelDefinition modelDefinition, IOrmLiteDialectProvider dialect)
+        {
+            ModelDefinition = modelDefinition;
+            Dialect = dialect;
+
+            int startPos = 0;
+            int endPos = reader.FieldCount;
+
+            Fields = new List<string>(endPos - startPos);
+
+            for (int i = startPos; i < endPos; i++)
+                Fields.Add(reader.GetName(i));
+
+            unchecked 
+            {
+                hashCode = 17;
+                hashCode = hashCode * 23 + ModelDefinition.GetHashCode();
+                hashCode = hashCode * 23 + Dialect.GetHashCode();
+                hashCode = hashCode * 23 + Fields.Count;
+                for (int i = 0; i < Fields.Count; i++)
+                    hashCode = hashCode * 23 + Fields[i].Length;
+            }
+        }
+
+        public override bool Equals (object obj)
+        {
+            var that = obj as IndexFieldsCacheKey;
+            
+            if (obj == null) return false;
+            
+            return this.ModelDefinition == that.ModelDefinition
+                && this.Dialect == that.Dialect
+                && this.Fields.Count == that.Fields.Count
+                && this.Fields.SequenceEqual(that.Fields);
+        }
+        
+        public override int GetHashCode()
+        {
+            return hashCode;
+        }
+    }
+}

src/ServiceStack.OrmLite/OrmLiteUtils.cs

@@ -31,6 +31,10 @@ public static class OrmLiteUtils
     {
         internal const string AsyncRequiresNet45Error = "Async support is only available in .NET 4.5 builds";
 
+        const int maxCachedIndexFields = 10000;
+        private static Dictionary<IndexFieldsCacheKey, Tuple<FieldDefinition, int, IOrmLiteConverter>[]> indexFieldsCache 
+            = new Dictionary<IndexFieldsCacheKey, Tuple<FieldDefinition, int, IOrmLiteConverter>[]>(maxCachedIndexFields);
+
         public static void DebugCommand(this ILog log, IDbCommand cmd)
         {
             var sb = StringBuilderCache.Allocate();
@@ -160,7 +164,7 @@ public static List<T> ConvertToList<T>(this IDataReader reader, IOrmLiteDialectP
                 }
                 return (List<T>)(object)to.ToList();
             }
-            if (typeof(T).Name.StartsWith("Tuple`"))
+            if (typeof(T).Name.StartsWith("Tuple`", StringComparison.Ordinal))
             {
                 var to = new List<T>();
                 using (reader)
@@ -491,12 +495,25 @@ public static Tuple<FieldDefinition, int, IOrmLiteConverter>[] GetIndexFieldsCac
             int startPos=0,
             int? endPos = null)
         {
+            var end = endPos.GetValueOrDefault(reader.FieldCount);
+            var cacheKey = (startPos == 0 && end == reader.FieldCount && onlyFields == null)
+                            ? new IndexFieldsCacheKey(reader, modelDefinition, dialect)
+                            : null;
+
+            if (cacheKey != null) 
+            {
+                lock (indexFieldsCache)
+                {
+                    if (indexFieldsCache.ContainsKey(cacheKey))
+                        return indexFieldsCache[cacheKey];
+                }
+            }
+
             var cache = new List<Tuple<FieldDefinition, int, IOrmLiteConverter>>();
             var ignoredFields = modelDefinition.IgnoredFieldDefinitions;
             var remainingFieldDefs = modelDefinition.FieldDefinitionsArray
                 .Where(x => !ignoredFields.Contains(x) && x.SetValueFn != null).ToList();
 
-            var end = endPos.GetValueOrDefault(reader.FieldCount);
             var mappedReaderColumns = new bool[end];
 
             for (var i = startPos; i < end; i++)
@@ -549,7 +566,20 @@ public static Tuple<FieldDefinition, int, IOrmLiteConverter>[] GetIndexFieldsCac
                 }
             }
 
-            return cache.ToArray();
+            var result = cache.ToArray();
+
+            if (cacheKey != null)
+            {
+                lock(indexFieldsCache)
+                {
+                    if (indexFieldsCache.ContainsKey(cacheKey))
+                        return indexFieldsCache[cacheKey];
+                    else if (indexFieldsCache.Count < maxCachedIndexFields)
+                        indexFieldsCache.Add(cacheKey, result);
+                }
+            }
+
+            return result;
         }
 
         private const int NotFound = -1;

src/ServiceStack.OrmLite/ServiceStack.OrmLite.Signed.csproj

@@ -249,6 +249,7 @@
     <Compile Include="Support\LoadList.cs" />
     <Compile Include="Support\LoadReferences.cs" />
     <Compile Include="UntypedApi.cs" />
+    <Compile Include="IndexFieldsCacheKey.cs" />
   </ItemGroup>
   <ItemGroup>
     <BootstrapperPackage Include="Microsoft.Net.Client.3.5">

src/ServiceStack.OrmLite/ServiceStack.OrmLite.csproj

@@ -243,7 +243,8 @@
     <Compile Include="Support\LoadList.cs" />
     <Compile Include="Support\LoadReferences.cs" />
     <Compile Include="UntypedApi.cs" />
-  </ItemGroup>
+    <Compile Include="IndexFieldsCacheKey.cs" />
+ </ItemGroup>
   <ItemGroup>
     <BootstrapperPackage Include="Microsoft.Net.Client.3.5">
       <Visible>False</Visible>